Fluoroplastics are known to offer a unique combination of chemical, electrical, and mechanical properties which makes them useful over a broad range of applications. One such fluoroplastic, polytetrafluoroethylene (PTFE), exhibits exceptional resistance to chemicals. Aqueous dispersions of PTFE have been used to impregnate fabrics to impart hydrophobic properties and resistance to chemicals, as shown, for example, in U.S. Pat. No. 4,342,675. PTFE coatings are most commonly achieved by contacting the surface to be coated with a dispersion containing about 45-50% solids, drying, and heating the resin particles to temperatures of 357.degree.-400.degree. C. to cause the particles to sinter and thereby bond to the surface. It has also been suggested that coatings with a degree of useful properties can be achieved at temperatures below that of the sintering temperature of TFE resin particles by either: (i) spray-coating the polymer surface with a volatile solvent for the polymer, sufficient to soften the surface, causing it to become tacky and thereby penetrable by the PTFE particles, as shown in U.S. Pat. No. 3,200,006; (ii) the use of pressure to embed the particles into the substrate, see for example DuPont Product Information Bulletin No. X-50G; or (iii) the use of chemical coupling agents (heavy metal organic complexes) which are capable of bonding both to the PTFE particles and the surface to be coated, see U.S. Pat. Nos. 3,968,297 and 4,232,087. However, these procedures will be of limited value for those substrates in which the dissolution thereof, the use of the compressive forces, or the use of contaminating chemicals would be a serious detriment to the coated surface, e.g., for membranes employed in filtration and medicinal applications.